Spark at distributor cap, but not at the plugs.

My roommate just bought an '86 with the old GM 2.8. I know POS. But hell it was only $600. Anyways, the jeep was running....barely, but it would drive. So we decided to do a tune-up. Changed the plugs, wires, dist. cap, rotor, cleaned all the grounds and checked the vac lines. Now it won't spark at the plugs. We took the ignition plug off the top of the cap, and hooked it up to an open spark plug. Big spark. Now we hook that back to the dist. and check the spark at the plugs...and only half the plugs spark. The 2,4,6 cylinders have spark, but the opposite side of the engine...cylinders 1,3,5, don't have any spark. Were in the process of looking for a 3.4, but we wanted to at least get on the trail first.

We even tried two dist. caps and two rotors, put the old stuff on and the same thing happens. Although when we did finalize everything, then egine started...ran for a min..then slowly died. Now it won't start.

I know someone here knows whats up. Help us out here..

re check your fireing order. you may be confused on which cylinders are 1,3,5. are you sure you installed the plug wires correctly? seems weird that one bank fires and not the other.

We checked, and re-checked. We also have one of those hanes manuals that has the firing order. I'm looking to get a FSM from a member on here, but don't have it yet.


Whats weird is how it started for a min, then died. Now there is nothing. We are getting a new ignition coil. Maybe there is just not enough spark. Also the alternator is getting replaced.

Check the coil, could be going bad.

have you tried switching the wires side to side? maybe you got a defective set?

Your sure that 1, 3, 5 arent getting any spark or could it possibly be a fuel issue?

Ok...So we put all of the old stuff back on. And bam. It runs. We decided that it was the plug wires. None of them are the same lengths as the wires that r in there. They are all either too long or too short. Not one of them matched. We went through two caps, two rotors, two coils, and 12 plugs....but only one set of wires...And with of the old stuff on, and the new wires on...no spark. It was just so hard to believe that it was the new wires. Whats weird is that we put all the old stuff on before...and nothing. I don't get it. But i'm glad its running now.

Thank you everyone for your help and suggestions. Anyone want to buy a Jeep?? It's for sale now. lol